In the electronics and semiconductor industries, systems used to test and qualify integrated circuit (IC) chips during the manufacturing process are conventionally referred to as “test systems.” FIG. 1 depicts a test system 100. The test system 100 includes an electrical connector for providing an electrical connection between an IC chip 110 and a printed circuit board (PCB) 120. The electrical connector can include a socket body 130, a plurality of spring probes 140, and a socket retainer 150.
FIGS. 2 and 3 depict the spring probe 140. The spring probe 140 can include a shell 241, a pair of plungers 243, and a spring 344. The shell 241 can be tubular and can be formed of copper alloy coated by nickel and gold. The plungers 243 and the spring 344 can be slidable inside the shell 241. The shell 241 can be crimped at both ends 242 to retain the plungers 243 and the spring 344 within the shell 241, and the spring 344 can bias the plungers 243 outwardly from the shell 241. Thus, the spring 344 is capable of exerting a force against each plunger 243 outwardly from the shell 241, and also the plungers 243 can be depressed inwardly into the shell 241 under a force directed inward against the spring 344.
The spring probe 140 can be inserted through and held within corresponding cavities in a socket body 130 and a socket retainer 150 in an array. FIGS. 4 and 5 show the spring probe 140 inserted into socket cavities 431 formed in the socket body 130 and the socket retainer 150. The socket body 130 and the socket retainer 150 can position the plungers 243 of the spring probes 140 such that the plungers 243 at a first end of the spring probes 140 electrically connect to conductive pads on the IC chip 110, and the plungers 243 at a second end of the spring probes 140 electrically connect to conductive pads on the PCB 120.
In the test system 100, an external surface of the spring probe 140 is formed with a diameter that is smaller than the diameter of an internal surface of the socket cavity 431 to allow the spring probe 140 to be inserted into the socket cavity 431 in the socket body 130. As a result, as shown in FIG. 5, a first gap 560 can be formed between the internal surface of the socket cavity 431 and the external surface of the shell 241.
Also, in the test system 100, an external surface of the plunger 243 inside the shell 241 is formed with a diameter that is smaller than the diameter of an internal surface of the shell 241 to allow the plunger 243 to be inserted into the shell 241. As a result, as shown in FIG. 5, a second gap 570 can be formed between the internal surface of the shell 241 and the external surface of the plunger 243.